League head of women's football Nicole Livingstone has said that the league would remain in constant dialogue with clubs as to their player availability status and would consider cases of special consideration if required.

Melbourne star Lily Mithen has been ruled out for at least the first three rounds following surgery on a syndesmosis injury in her right ankle, taking the Demons' available players to just 24 after Bianca Jakobsson stepped away for work commitments.

Demons football operations manager Daniel McPherson admitted that the club had "certainly discussed" contacting the league to look into whether top-up players could be considered earlier than the "very low" threshold.

Lily Mithen will miss the start of the AFLW season. Picture: Getty

"We want to be ahead of the game a little bit in terms of being prepared for that, if it comes to that," he said.

"Obviously we're hoping that it doesn't get to that, but it's a pretty tight line. When you start with a list of 30, it doesn't take too much bad luck to get down to that threshold. We're constantly discussing train-on players, and their ability to be able to play if needed, and replacement players.

"We certainly don't need any more injuries.

"It's a pretty low number. If things are pretty bad by the time you've got to put those things in place."

League women's football boss Nicole Livingstone said last week that the AFL would continue to speak with clubs regarding what could be considered "exceptional circumstances".

But with the season kicking off on Friday, McPherson said the time might be running out.

"I don't know whether they'll do much with it now given we're right on the doorstop of the season, but I think already they're discussing that it'll have to be looked at again before next season starts," he said.

Jess Duffin won’t play this season after announcing she’s pregnant.

North Melbourne was allowed to promote a player to replace Jess Duffin, who announced on New Year's Eve that she was pregnant.

"There's been a lot of discussions about list size in terms of the activation of once it reaches 23, being able to top players up," Livingstone said.

"We did make a determination on an application from North Melbourne about Jess Duffin's replacement. We do view pregnancy as different to illness or injury.

"We continue to speak to the clubs, and we've said to them that if they feel they have any exceptional circumstances to be able to elevate train-ons to top-ups, then they can come to us."

Mithen has been felled with a syndesmosis injury sustained in the Demons' practice match against Collingwood and will not play until at least Round 4.

"We expect her to hopefully be back in four or five weeks," McPherson said.

"She'll probably miss the first three games and hopefully she'll be around the mark after that.

"After the two girls that had the knees either side of Christmas (Katherine Smith and Shae Sloane) it's like, gee whiz, we don't want any more.

"Hopefully she's back pretty quickly. Fingers crossed."

McPherson said ruck Tegan Cunningham - who sustained a minor quad strain a few weeks ago - would play this weekend.

"Provided that she gets through training this week, we expect her to play, which will be great," he said.